"Et tu Brute?" Imagine your best friend ends up literally stabbing you in the back. Why? He's about to become King which is a four letter word in ancient Rome and the Senators feel they need to do away with Caesar before he becomes unstoppable. Never mind all of the things he has already done and that naming him King will not really give him any extra power because he rules over everything undaunted as it is. The senate was not justified in killing Caesar because he accomplished an enormous amount of great achievements in his lifetime, he possessed many qualities that make an outstanding leader, and the senate was wrong in the sense that killing the dictator would solve the problems.
The fact the Julius Caesar had accomplished an incredible amount of great achievements in his lifetime alludes to the inference that he would have kept achieving if it wasn't for his assassination by the senate. In this sense, killing him was actually counterproductive to the growth and development of the Roman Empire. For example, he patiently handled the problem of debt, created the Julian calendar, built a new forum, reduced the Civil Code to manageable proportions, provided public libraries, drained the Pomptine Marshes, subsidized public works and entertainment, standardized the system of tax collections throughout the empire, and much more. It is a fair conclusion to assume that if Caesar were kept alive to live through his term, he would not undo these achievements, but rather make them better and likely accomplish new ones. .
Julius Caesar possessed many qualities that are characteristic of great rulers. Qualities such as endurance, determination, and commitment. He always led his army, more often on foot than in the saddle, went bareheaded in the sun and rain alike, and could travel for long distances at incredible speed in a gig, taking very little luggage. If he reached an unfordable river he would either swim across it on an inflated skin; and often arrived at his destination before the messengers whom he had sent ahead to announce his approach.